DOC: Update Changelog

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * New exceptions `HTTPAuthorizationException` and
   `ResourceNotFoundException` for HTTP 403 and 404 errors,
   respectively.
+* `BadQueryError`, `EmptyUniqueQueryError`, and `QueryNotUniqueError`
+  for bad (unique) queries.
 * Versioning support (experimental).
 
 ### Changed ###
@@ -26,6 +28,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `get_entities` and `get_all_entities`. The `has_error` method can be
   used to check whether a `TransactionError` was caused by a specific
   `EntityError`.
+* Unique queries will now result in `EmptyUniqueQueryError` or
+  `QueryNotUniqueError` if no or more than one possible candidate is
+  found, respectively.
 
 ### Deprecated ###